Finite volume method analysis of heat transfer problem using adapted strongly implicit procedure

A fixed grid based accurate phase-field method for dendritic solidification in complex geometries

A stable and efficient hybrid scheme for viscous problems in complex geometries

Radiative heat transfer in a complex two-dimensional enclosure with an absorbing, emitting, and isotropically scattering gray medium is investigated by using the finite-volume method. In particular, an implementation of the unstructured polygonal meshes, based on an unstructured triangular system, is introduced, thereby reducing the computation time required for the analysis of thermal radiation. By connecting each center point of the triangular meshes rather than joining the centroids of the triangular elements to the midpoints of the corresponding sides to form a polygonal element, it not only prevents concave shapes of adjacent faces, it also reduces the number of control-volume faces of the polygonal mesh. After a mathematical formulation and corresponding discretization equation for the radiative transfer equation are derived, the final discretization equation is introduced with the conventional finite-volume approaches. The present formulation is then validated by comparing results with those obtained in previous related works. All the results presented in this work show that the present method is accurate and computationally efficient for the analysis of radiative heat transfer problems in complex geometries.

Prediction of radiative heat transfer in 2D irregular geometries using the collocation spectral method based on body-fitted coordinates

Temporally and spatially unstable thermal conditions lead to transient or inhomogeneous thermo-elastic behavior of workpieces during manufacturing or geometric inspection. Temperature monitoring by means of sensors consign transient temperature fields, but do not yield information about the heat flow acting as thermal boundary condition, which is a relevant input parameter for nearly any thermal simulation. Addressing the need for efficient methods, the authors propose an approach to solve inverse heat transfer problems in complex geometries. In the presented study, locally acting heat loads are experimentally investigated based on virtual demonstrators running in FEM. The conducted method shows high potential for transient heat flow modelling in terms of accuracy and computational efficiency.

As computational fluid dynamics (CFD) simulations still take a lot of time in industry for design optimization analyses, we propose to reduce the number of required CFD simulations considerably using a new meta-algorithm. The algorithm consists of employing kriging in conjunction with simulated annealing (SA) as a design tool. The method enables effective and fast design optimization for complex fluid flow systems. In this paper, it is applied to a convective heat transfer problem in a channel with periodic heat sources with constant heat flux. We show that the geometry optimization of two dimensional thermo-fluids problems in complex geometries is made more effective and faster using kriging-simulated annealing meta-algorithm.

While the Anomaly flow was originally motivated by string theory, its zero slope case is potentially of considerable interest in non-Kahler geometry, as it is a flow of conformally balanced metrics whose stationary points are precisely Kahler metrics. We establish its convergence on Kahler manifolds for suitable initial data. We also discuss its relation to some current problems in complex geometry.

A procedure to obtain accurate solutions for many transient conduction problems in complex geometries using a Galerkin-based integral (GBI) method is presented. The nonhomogeneous boundary conditions are accommodated by the Green’s function solution technique. A Green’s function obtained by the GBI method exhibits excellent large-time accuracy. It is shown that the time partitioning of the Green’s function yields accurate small-time and large-time solutions. In one example, a hollow cylinder with convective inner surface and prescribed heat flux at the outer surface is considered. Only a few terms for both large-time and small-time solutions are sufficient to produce results with excellent accuracy. The methodology used for homogeneous solids is modified for application to complex heterogeneous solids.

The limiting hole pressure in three dimensions

On the Finite Difference-Based Lattice Boltzmann Method in Curvilinear Coordinates

SummaryThis study documents the first attempt to extend the singular boundary method, a novel meshless boundary collocation method, for the solution of 3D elasticity problems. The singular boundary method involves a coupling between the regularized BEM and the method of fundamental solutions. The main idea here is to fully inherit the dimensionality and stability advantages of the former and the meshless and integration‐free attributes of the later. This makes it particularly attractive for problems in complex geometries and three dimensions. Four benchmark 3D problems in linear elasticity are well studied to demonstrate the feasibility and accuracy of the proposed method. The advantages, disadvantages, and potential applications of the proposed method, as compared with the FEM, BEM, and method of fundamental solutions, are also examined and discussed. Copyright © 2015 John Wiley & Sons, Ltd.

A depth-averaged 2-D numerical model for unsteady tidal flow in estuaries is established using the finite volume method on non -staggered, curvilinear grid. The 2-D shallow water equations are solved by the SIMPLEC algorithm with the Rhie and Chow’s momentum interpolation technique. The convection terms are discretized by one of the hybrid upwind/central difference scheme, exponential difference scheme, QUICK scheme and HLPA scheme. The algebraic equations are solved using the strongly implicit procedure (SIP). The model is capable of handling the drying and wetting problem due to the variation of water surface elevation. The model has been tested in Tokyo Bay and San Francisco Bay. The tests show that the present model is very stable and efficient. The simulated water elevation and flow velocit y are in good agreement with the measured data.

In this paper, the leading edge film-cooling flow field of a heavy duty gas turbine cascade has been studied by central difference scheme and multi-block grid technique. The research is based on the three-dimensional N-S equation solver. By way of comparison and analysis of the temperature field, the distribution of profile pressure, and the distribution of film-cooling adiabatic effectiveness in the region of leading edge with different cool air mass and injection angles, it is found that the aerodynamic energy loss drops a little by adding the cool air, the distribution of temperature of the blade is obviously changed and the adiabatic effectiveness at the leading edge and suction side is higher than that on pressure side. Profile pressure is not changed obviously in the whole, with the exception in the local region near the cooling holes. The change of the pressure variation is greater on the suction side. The influence of the change of cool air mass and injection angles on the flow field near the leading edge is obviously.

In this paper, the trailing edge film cooling flow field of a heavy duty gas turbine cascade has been studied by central difference scheme and multi-block grid technique. The research is based on the three-dimensional N-S equation solver. By way of analysis of the temperature field, the distribution of profile pressure, and the distribution of film-cooling adiabatic effectiveness in the region of trailing edge with different cool air injection mass and different angles, it is found that the impact on the film-cooling adiabatic effectiveness is slightly by changing the injection mass. The distribution of profile pressure dropped intensely at the pressure side near the injection holes line with the large mass cooling air. The cooling effect is good in the region of trailing edge while the injection air is along the direction of stream.

The urgency of constructing spatial curvilinear grids in areas with complex geometry is formulated. An overview of the construction of two-dimensional curvilinear computational grids is given. The article describes the rationale for the fact that the methods described in the review cannot fully calculate the flow parameters in regions with complex geometry. A method for constructing three-dimensional grids for bodies with arbitrary surface geometry is described. The results of constructing a three-dimensional grid are presented using a hemisphere as an example. An estimate of the measures of non-orthogonality for the test case is given.